Add info command

[interstateone]

Add an info command that outputs information about a specific version, whether or not it's installed. This is most useful with the Xcode Releases data source, which is now the default.

This should output similar static information about the version as is displayed in the Xcodes.app info pane, including:

• Download file size if not installed, or size on disk if installed
• Release date
• Compatibility
• Included SDKs
• Included compilers
• Link to release notes

Output should use appropriate formatting when in an interactive terminal. For example, bold headings, but probably not any color unless it would be meaningful. If data is output in columns, align the columns in an interactive terminal so it's easier for a human to read. In a non-interactive terminal columns should be tab-separated.

[fishcharlie]

It would also be cool if there was a flag for this to output in JSON!